Abstract: An inverter is the interface of the distributed generation in micro-grids. With the increasing proportion of renewable energy, the operation of inverters in parallel becomes a key technology. In this case, the droop control method without communication interconnection is widely used in micro-grids. For the inverter parallel control system, the basic principle of traditional droop control method is analyzed. Because of the different impedances of the transmission line, the accurate distribution of reactive power is affected by the control method. Therefore, an improved droop control method based on PI regulator is presented. Matlab/Simulink simulation software is used to verify the correctness and effectiveness of the proposed control method.